/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.s4.core.window;

/**
 * A convenience window slot, that aggregates elements of type <T>.
 * 
 * Users must add suitable getter methods to retrieve aggregated data.
 * 
 * @param <T>
 *            elements to aggregate
 */
public interface Slot<T> {

    /**
     * Add a single data element
     */
    void update(T data);

    /**
     * Compute aggregated data on available gathered slot data, place slot and slot data in immutable state.
     */
    void close();

}
